Influence of light guide tip used in the photo-activation on degree of conversion and hardness of one nanofilled dental composite

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Increased Androgen Receptor and Remodeling in the Prostatic Stroma After the Inhibition of 5-Alpha Reductase and Aromatase in Gerbil Ventral Prostate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of malathion and cadmium on acetylcholinesterase activity and metallothionein levels in the fish Seriola dumerilli

The potential use of acetylcholinesterase (AChE) and metallothionein (MT) responses as biomarker of organophosphorous (OPs) and trace metal were assessed in fish Seriola dumerilli exposed to 0, 4, 6 mg/kg of malathion for 2, 7 and 13 days, and to 0, 50, 100, 250 mu g/kg of Cd for 2 days. Brain AChE was significantly inhibited after 2 and 7 days of malathion exposure, in a dose-response manner, but no inhibition was observed after 13 days of exposure. When exposed to Cd for 2 days, S. dumerelli presented an increase in AChE activity at a concentration of 50 mu g/kg, but a strong and dose-dependent AChE inhibition at 100 and 250 mu g/kg. Cd treatment also caused a rapid increase in MTs concentration in liver, even at the lower concentration. Our experiments indicate that the measurement of hepatic MT concentration and brain AChE activity in S. dumerilli would be useful biomarkers of OP and Cd exposure and/or effects.

Mercury Redox Chemistry in the Negro River Basin, Amazon: The Role of Organic Matter and Solar Light

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Major Aspects of the Mercury Cycle in the Negro River Basin, Amazon

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Intraosseous foreign-body granuloma in the mandible subsequent to a 20-year-old work-related accident

The purpose of this article was to describe the clinical and microscopic features of an intraosseous foreign-body granuloma in the mandible that developed after the traumatic implantation of metal fragments during a work-related accident. A 65-year-old male patient had a severe pain in the body of mandible. Clinical examination showed facial asymmetry and a scar, extending to the left mental region. Intraoral examination revealed a soft mass involving the left alveolar bone with normal appearance of the mucosa surface. Panoramic radiographs showed a radiolucent lesion along the mandible extending from the central incisive to the first molar. Computed tomography revealed an osteolytic mass in the same area. His medical history included a work-related accident twenty years prior to evaluation. During the biopsy an important amount of bright metal-like pieces surrounded by soft tissue were found. A microscopic examination showed a foreign body associated with an aggregation of multinucleated giant cells. The final diagnosis was a foreign body granuloma. Even though foreign-body granulomas in the mandible are rare lesions, dentists should be familiar with their features and include them in the differential diagnosis of tissue masses.

Deciphering the weathering processes using environmental mineralogy and geochemistry: Towards an integrated model of laterite and podzol genesis in the Upper Amazon Basin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Composition-resolved size distributions of volcanic aerosols in the Mt. Etna plumes

Particle size distributions for soluble and insoluble species in Mt. Etna's summit plumes were measured across an extended size range (10 nm < d < 100 mu m) using a combination of techniques. Automated scanning electron microscopy (QEMSCAN) was used to chemically analyze many thousands of insoluble particles (collected on pumped filters) allowing the relationships between particle size, shape, and composition to be investigated. The size distribution of fine silicate particles (d < 10 mu m) was found to be lognormal, consistent with formation by bursting of gas bubbles at the surface of the magma. The compositions of fine silicate particles were found to vary between magmatic and nearly pure silica; this is consistent with depletion of metal ions by reactions in the acidic environment of the gas plume and vent. Measurements of the size, shape and composition of fine silicate particles may potentially offer insights into preemission, synemission, and postemission processes. The mass flux of fine silicate particles from Mt. Etna released during noneruptive volcanic degassing in 2004 and 2005 was estimated to be similar to 7000 kg d(-1). Analysis of particles in the range 0.1 < d/mu m < 100 by ion chromatography shows that there are persistent differences in the size distributions of sulfate aerosols between the two main summit plumes. Analysis of particles in the range 0.01 mu m < d < 0.1 mu m by scanning transmission electron microscopy (STEM) shows that there are significant levels of nanoparticles in the Mt. Etna plumes although their compositions remain uncertain.

Placentation in the rock cavy, Kerodon rupestris (Wied)

Rock cavies are rodents found in the semi-arid caatinga of Brazil. We studied the structure of the rock cavy placenta by light and transmission electron microscopy. The exchange area of the labyrinth was organized in lobes separated by interlobular areas. The interhaemal barrier was syncytial haemomonochorial. The syncytiotrophoblast had recesses in the basal membrane and some invaginations of the apical membrane, but transtrophoblastic channels could not be found. The interlobular regions comprised syncytiotrophoblast, enclosing maternal venous blood channels, and cytotrophoblast. There was a prominent subplacenta composed of cytotrophoblast and syncytiotrophoblast. Microvilli projected into spaces between the cytotrophoblasts and into lacunae within the syncytiotrophoblast. The yolk sac epithelium exhibited coated pits, endocytotic vesicles and larger vacuoles, consistent with a role in protein uptake from the uterine lumen. Tight junctions between these cells provided a barrier to diffusion by the intercellular route. The reproductive biology of the rock cavy differs from other members of the family, including the guinea pig, but the architecture of the placenta remains remarkably constant. (c) 2004 Elsevier Ltd. All rights reserved.

Cleavage of the dimeric cyclopalladated [Pd(N,C-dmba)(mu-X)](2), (dmba = N,N-dimethylbenzylamine; X = SCN and NCO) by diphosphines. Palladium(II) compounds with distinct structures in the solid-state and in solution

The reactions of the pseudohalide-bridged dimer [Pd(N,C-dmba)(mu -SCN)](2) (1) (dmba = N,N-dimethylbenzylamine) with cis-Ph2PCH=CHPPh2 (cis-dppet) (1:1 molar ratio) and of [Pd(N,C-dmba)(mu -NCO)](2) (2) with Ph2PCH2CH2PPh2 (dppe) (1:2 molar ratio) gave mononuclear [Pd(C-dmba)(SCN)(cis-dppet)].H2O (1a) and [Pd(C-dmba)(NCO)(dppe)] (2a), respectively, with the diphosphines acting as chelating ligands. Reaction of (2) with Fe(C5H4PPh2)(2) (dppf) (1:1 molar ratio) yielded [{Pd(N,C-dmba)(NCO)}(2)(mu -dppf)] (2b), a bimetallic species containing two palladium atoms bridged by the diphosphine, whereas reaction in a 1:2 molar ratio gave the mononuclear [Pd(N,C-dmba)(dppf)][NCO]. CH2Cl2 (2c), with the diphosphine acting as a chelating ligand. The compounds have been characterized by elemental analysis, i.r., P-31{H-1}, C-13- and H-1-n.m.r. spectroscopies. Conductivity measurements together with spectroscopic data showed that (1a) and (2a) do not have the same structure in the solid state and in MeCl solution, whereas for compounds (2b) and (2c) no structural changes were observed when the solids were dissolved in MeCl.

Glasses in the SbPO4-WO3 system

Glasses in the binary system (100 - x)SbPO4-xWO3 (20 <= x <= 60, x in mol%) have been prepared and characterized. Differential thermal analysis (DTA) shows that the glass transition temperature, T-g increases from 412 degrees C, for samples containing 20 mol% of WO3 to 481 degrees C observed for glass containing 60 mol%. Sample containing 40 mol% in WO3 were observed to be the most stable against devitrification. The structural organization of the glasses has been studied by using Fourier transform infra-red (FTIR), Raman, P-31 Magic angle spinning (MAS) and spin echo nuclear magnetic resonance (NMR) spectroscopies. Results suggest two distinct networks comprising the glass structure, one with high SbPO4 content and the other characteristic of the highest WO3 content samples. The glasses present photochromic properties. Colour changes are observed for samples after exposure to ultraviolet or visible laser light. XANES, at L-1 absorption edge of tungsten, suggests partial reduction from W6+ to W5+ species during the laser irradiation. The photochromic effects and the colour changes, promoted by laser excitation, are reversible and easily removed by heat for during 1 h at 150 degrees C. Subsequent 'write/erase' cycles can be done without degradation of the glasses. (C) 2007 Elsevier B.V. All rights reserved.

Physico-chemical parameter correlations in the [RuCl2(CO)(L)(PPh3)2] complexes (L = N-heterocycles)

Fourteen complexes in the series [RuCl2(CO)(L)(PPh3)2] (where L = N-heterocycles) have been prepared and characterized by IR and NMR spectroscopies, and cyclic voltammetry. A good correlation is found between observed and calculated electrochemical potentials; E1/2 vs pKa or (Gp, σm for a series of similar ligands. It is now reported that the carbonyl stretching frequency, νCO, and the 13C and 31P NMR signals do not correlate well with any of the physico-chemical parameters used (E1/2, Taft's and Hammett's parameters). This behaviour is probably due to the characteristics of the Ru(II) species, which does not transmit the steric and electron donor/acceptor properties of the ligands to the carbonyl group, or because the measurements are not able to detect the effect induced by the changes in the ligand L. Indeed, good correlations are obtained when the measurements directly involve the metal centre, as is the case in the E1/2 measurements. Crystals of o[RuCl2(CO)(4-pic)(PPh3)2] are monoclinic, space group P21/n, a = 12.019(2), b = 13.825(3) and c = 22.253(3) . The structure was solved by the Patterson method and was refined by full-matrix least-squares procedure to R = 0.054 and Rw = 0.055, for 2114 reflections with I > 3σ(I). For L = 2-acetylpyridine and 2-methylimidazole, complexes with formulae [RuCl2(CO)(L)(PPh3)] · L and [RuCl2(CO)(L)2 (PPh3)], respectively, were obtained. © 1998 Elsevier Science Ltd. All rights reserved.

Utilizing the CORBA platform in the construction of a highly immersive virtual environment

This article presents the implementation of a distributed system of virtual reality, through the integration of services offered by the CORBA platform (Common Object Request Broker Architecture) and by the environment of development of 3D graphic applications in real time, the WorldToolkit, of Sense8. The developed application for the validation of this integration is that of a virtual city, with an emphasis on its traffic ways, vehicles (movable objects) and buildings (immovable objects). In this virtual world, several users can interact, each one controlling his/her own car. Since the modelling of the application took into consideration the criteria and principles of the Transport Engineering, the aim is to use it in the planning, project and construction of traffic ways for vehicles. The system was structured according to the approach client/server utilizing multicast communication among the participating nodes. The chosen implementation for the CORBA was the Iona's ORBIX software. The performance results obtained are presented and discussed in the end.

Variational studies and replica symmetry breaking in the generalization problem of the binary perceptron

We analyze the average performance of a general class of learning algorithms for the nondeterministic polynomial time complete problem of rule extraction by a binary perceptron. The examples are generated by a rule implemented by a teacher network of similar architecture. A variational approach is used in trying to identify the potential energy that leads to the largest generalization in the thermodynamic limit. We restrict our search to algorithms that always satisfy the binary constraints. A replica symmetric ansatz leads to a learning algorithm which presents a phase transition in violation of an information theoretical bound. Stability analysis shows that this is due to a failure of the replica symmetric ansatz and the first step of replica symmetry breaking (RSB) is studied. The variational method does not determine a unique potential but it allows construction of a class with a unique minimum within each first order valley. Members of this class improve on the performance of Gibbs algorithm but fail to reach the Bayesian limit in the low generalization phase. They even fail to reach the performance of the best binary, an optimal clipping of the barycenter of version space. We find a trade-off between a good low performance and early onset of perfect generalization. Although the RSB may be locally stable we discuss the possibility that it fails to be the correct saddle point globally. ©2000 The American Physical Society.